Temperature and moisture control within the attic space of a building structure are critical. With respect to temperature, the air conditioning load is intensified by the thermal storage effect associated with the attic air space found in most dwellings. Air circulates very slowly in the attic air space so that its temperature rises rapidly as solar radiation is absorbed. As a result, a large amount of heat is transferred from the exposed roof structure to the air trapped within the attic air space. With respect to moisture control, by way of example, in cold weather, a combination of high, inside relative humidity and low outside temperature may cause condensation on the underside of the roof sheathing. If the moisture is not removed, the resulting condensate may cause insulation and construction materials to deteriorate. In light of the foregoing, an ongoing need exists for improved attic ventilation systems which ensures proper thermal and moisture control in building structures, including many types of residential homes, having attic spaces.